Circuit breaker



1958 R. c. DlCKlNSON ET AL 2,366,043

CIRCUIT BREAKER 4 Sheets-Sheet 1 Filed Aug. '23, 1955 Dec. 23, 1958 R.c. DlCKlN SON ET AL 2,856,043

CIRCUIT BREAKER 4 Sheets-Sheet 2 Filed Aug. 23, 1955 Dec. 23, 1958 R. c.DICKINSON ET AL 2,866,043

CIRCUIT BREAKER Filed Aug. 23, 1955 4 Sheets-Sheet 3 Fig.4.

WITNESSES INVENTORS Robert C. Dickinson 8 W Poul Olsson.

Dec. 23, 1958 R. c. DICKINSON ET AL 2,866,043

CIRCUIT BREAKER 4 Sheets-Sheet 4 Filed Aug. 23, 1955 Fig. 5.

United States Patent .0 M

CIRCUIT BREAKER Robert Charles Dickinson and Paul Olsson, Penn Township,Allegheny County, Pa., assignors to Westinghouse Electric Corporation,EastPittsburgh; Pa., :1 corporation of Pennsylvania Application August23, 1955, Serial No. 530,062

13 Claims. (Cl. 200144) This invention relates to circuit interruptersand more particularly to air circuit interrupters for interrupting highvoltages.

An object of the invention is to provide a clrcuit interrupter embodyingan improved contact structure. I

Another object of the invention is to provide a circuit interrupterembodying self-aligning contacts. I

Another object of the invention is to provide a circuit interrupter inwhich the contact structure is disposed within a U-shaped channel frameof molded insulating material.

Another object of the invention is to provide a circuit interrupter inwhich the contact structure is disposed within a U-shaped channel frameof molded insulating material and in which the terminal studsandbushings are mounted on the insulating frame without the use of ametal frame or metal flanges.

Another object of the invention is to provide-a circuit interrupterembodying an arc chute which is hinged on the upper contact block.

The invention both as to structure and operation, to gether withadditional objects. and advantageslthereof, will be best understood fromthe following description thereof when read in conjunction with theaccompanying drawings.

In said drawings:

Figure 1 is a side elevational view of one of the pole units of thecircuit interrupter.

Fig. 2 is a detail sectional viewshowing theihinge arrangement for thearc chute.

Fig. 3 is a perspective view of the circuit interrupter with one of thearc chutes shown in the hinged'open position.

Fig. 4 is a vertical sectional view'taken through one of the pole unitsshowing the contact structure.

Fig. 5 is an enlarged elevational view, partly in section, showing thecontact structure.

The circuit interrupter comprises generally a plurality of pole unitassemblies 11 (Fig. 1) which are individually mounted on a basestructure. 13. Since the pole units are the same onlyone will bedescribed. The'pole unit comprises a channel-shaped frame 15 ofhi'ghstrength molded insulating material rigidly mounted on the base 13my means of a bracket 17 (Figs. land 4) secured to the ba e 13 bv meansof bolts 19, the frame 15-being secured to the bracket by bolts 21, onlyone 'being shown.

' blocks or feet 35 and 37 respectively brazed or otherwise suitablysecured to their inner ends. studs 31 and 33 respectively are insulatingbushings 32 Surrounding, the

and 34 which extend into suitable openings in cylindrical 2,866,043Patented Dec. 23, 1958 extensions 36 and 38 molded integral with therear wall of the insulating channel frame 15. The inner ends of thebushings 32-34 have beveled o-r conical surfaces 40 thereon which engagewith similar surfaces on the frame 15 with resilient washers 42 betweenthe surfaces. The purpose of the washers 42 is to take up any slightirregularities in the conical surfaces upon tightening of nuts 44 whichare threaded onto the outer ends of the studs 31-33, thereby providingfor accurate positioning and alignment of the studs. Making thechannel-shaped frame 15 of a high-strength insulating material permitsmounting the studs 3133 and the bushings 3234 directly on the framewithout the use of the conventional metal flanges on the bushings. Thisreduces the size and cost of the circuit interrupter.

The upper block 35 supports the stationary main contacts 39 and thestationary arcing contact 41. The stationary main contacts 39 of whichthere are four for each pole unit (see Fig. 3) are pivotally supportedinside an overhanging portion 43 on the block 35 and are biasedoutwardly by springs 45 to the closed contact position. A stop member 47is secured to the lower portion of the block 35 by bolts 49 to limitpivotal movement of the contact members 39. Each of the contact members39 has a slot 51 therein which engages a pin 53 projecting from theblock 35 to hold the contacts in alignment. The stationary arcingcontact member 41 is secured to the top portion of the block 35 by abolt 55. The upper contact block 35, together with a hinge projection113, the lower contact block or contact hinge member 37 and thestationary arcing contact 41 are all made from extruded sections therebyfurther reducing the cost of the circuit interrupter.

Spaced switch arms 57 (Figs. 3, 4 and 5) are formed from fiat copperpunchings and are pivotally mounted one on each'side of the lower blockor contact hinge member 37, by a bolt 59 and nut 61. A spring washer 63compressed between the nut 61 and one of the switch arms 57 providesgood electrical contact between the block 37 and the switch arms 57. Amovable main contact member 65 is rigidly mounted by means of bolts 67between the movable switch arms 57 and has a wide contact portion 69 forcooperating with all of the stationary contact members 39 for its poleunit. A movable arcing contact member 71 is provided with integraltrunnions 73 which extend from opposite sides thereof and pivotallyengage pivot recesses 75 in the upper ends of the switch arms 57. Thetrunnions 73 and the moving arcing contact member 71 are held inposition by a clip 77 mounted by means of a bolt 79 on the moving maincontact member 65. The moving arcing contact member 71 is electricallyconnected to the main moving contact member 65 by a flexible conductor81 having its upper end secured by means of a screw 83 to a projection85 of the moving arcing contact and its lower end secured to the mainmovable contact member by a bolt 87. The bolt 87 also secures an angularbracket 89 to the main moving contact member 65.

The moving arcing contact 71 is biased in a clockwise direction to theclosed contact position by springs 91 compressed between a washer 93bearing against the bracket 89 and a washer 95 which bears against themoving arcing contact 71. A rod 97 having one end pivotally con- .nectedby a pin 99 to the moving arcing contact 71 extends axially through thecoil springs 91 and through an opening in the bracket 89. The lower endof the rod 97 is threaded to receive a not 101 and a spacer 103 ismounted on the rod between the nut 101 and the bracket 89. The nut 101serves as an adjustable stop to limit the movement of the moving arcingcontact 71 relative to the switch arms 57 and the rod 97 acts as a guidefor the springs 91.

Pivotally connected to each of the moving contact structures by meansofa pin 105, is an operating rod 107. The operating rod 107 for each ofthe poles of the breaker at its lower end is connected to a common crossbar (not shown) but which is operated by a suitable operating mechanismto move the movable contact structure for all of the poles to open andclosed positions in unison.

The operating mechanism may be of any suitable type but is preferably ofthe general type disclosed in Patent No. 2,515,994, issued July 18, 1950to Joseph D. Findley, Jr., Alvin W. Ogg and Fritz E. Florschutz andassigned to the assignee of this invention. The operating mechanismdisclosed in this patent includes the common bar to which the operatingrods for the several poles of the interrupterare connected for unitarymovement, trip means for tripping the circuit interrupter free of theoperating mechanism and a closing solenoid for actuating the operatingmechanism to close the interrupter. The operating mechanism and themovable contact structure for all of the poles of the interrupter arereleasably held in closed position by the trip mechanism and are biasedin opening direction by the springs 45 and 91 and by spring means (notshown) on the operating mechanism.

When the trip mechanism functions in response to an abnormal circuitcondition, as fully described in the previously mentioned Patent No.2,515,994, the operating mechanism is released whereupon the operatingrods 107 are moved downwardly and the moving contacts are moved quicklyto the open position about pivot 59.

The main current path through the interrupter is from the upper terminal31 (Figs. 4 and through contact block 35, the main stationary contacts39, the main moving contact 69, the moving switch members 5'7 and theconducting block 37 to the lower terminal 33. A parallel current path isformed from the upper terminal 31 through contact block 35, thestationary arcing contact 41, the moving arcing contact 71, through theflexible conductor 81 and the moving switch members 57 to the lowerterminal 33. In the closed position of the interrupter the magneticeffect of the current loop through the main contacts 39-69 tends to blowthe main contacts on. When the main contacts separate during an openingoperation the main current loop is shifted to the arcing contacts and,as the arcing contacts separate, the magnetic effect of the current looptends to blow the are established by separation of the arcing contactsupwardly away from the contacts and into an arc chute 109 (Figs. 1 and5).

The arc chute may be of any suitable type such, for instance, as the arcchute disclosed in Patent No. 2,692- 319, issued October 19, 1954 to R.C. Dickinson and R. E. Frink and assigned to the assignee of thisinvention. The are chute comprises generally a pair of serially relatedstacks of arc extinguishing plates and blowout magnetic means forcontrolling and extinguishing the arc established by separation of thearcing contacts.

The arc chute 109 is hinged to the frame by means of a pin 111 (Figs. 1,2 and 3) supported in the rearwardly extending hinge portion 113 of theupper contact block 35. The pin 111 pivotally supports a bracket 115secured by means of bolts 117 to the arc chute housing 119 which is ofinsulating material. The bolts 117 threadedly engage a rear arc horn 121and also support a spring contact member 123 on the lower rear portionof the arc chute which engages the portion 113 of the upper contactblock 35. The lower end of a front are horn 125 (Fig. 4) is disposedagainst a resilient conducting member 127 secured by means of a bolt 129to the lower portion of the front wall of the arc chute housing. Alsosecured to the arc chute housing adjacent the lower end of theconducting strip 127 by means of a bolt 131 is the upper end of aconducting strip 133 all size of the circuit interrupter.

4 having its lower end secured to the lower contact block 37 by the bolt59.

Following separation of the main contacts, during an opening operation,the current loop is shifted therefrom to the arcing contacts and, as thearcing contacts separate, the magnetic effect of the current loop tendsto blow the are, established by separation of the arcing contacts,upwardly into the arc chute 109. Due to the presence of the magneticblowout coil (not shown) in the arc chute, the arc is further distortedand elongated until the end thereof at the stationary arcing contact istransferred to the rear arc horn 121 over the hinge projection 113,spring contact 123 and bolts 117 to the rear arc horn. As the movingcontact structure moves to the open position the moving arcing contactcomes into proximity to the forward arc horn 125, whereupon the end ofthe are at the moving arcing contact is transferred to the forward arc.born.

In the normal position of the arc chute the lower edges of the arc chutehousing rest on ledges 135 (Figs. 3, 4 and 5) molded on the side wallsof the insulating frame 15. By removing the bolt 131 the arc chute maybe swung backwardly about the hinge pin 111 to the position shown inFig. 3 to provide access to the contact structure. The arc chute and thechannel member meet and form continuous side barriers which separate ona line below the top, of the contacts to permit inspection of thecontacts. The resilient conducting member 127, which is secured to thelower part of the front of the arc chute by the bolt 129, is in contactwith the lower end of the front are horn 125 and, in the normal orclosed position of the arc chute is in contact with the upper end of theconducting strip 133. When the bolt 131 is removed and the arc chute ishinged back to the Fig. 3 position the contact between the conductingstrips 127 and 133 is broken. This contact is automaticallyreestablished when the arc chute is moved to its normal position (Fig.4) and the bolt 131 is secured in place.

. The invention provides a circuit interrupter having a channel-shapedframe of one-piece molded high-strength insulating material in which thestationary and movable contact structures are supported and enclosed.This permits mounting the terminals and the bushings therefor directlyon the molded insulating frame without the use of metal flanges on thebushings thus reducing the over- By providing a separate biasing springfor each of the several main contact fingers the main stationarycontacts are made self-aligning. The contact structure is made readilyaccessible by hinging the arc chute so that it can be pivotally movedout of the way. By making the contact blocks or feet and the stationaryarcing contacts of low cost extrusions the cost of the circuit breakeris reduced. The cost is further reduced by making some of the parts,including the moving switch arms, from flat punchings. The eliminationof the metal mounting frame and metal flanges for mounting the terminalbushings also contributes to the low cost of the circuit interrupter.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is to be understood that various changes inthe structural details and arrangement of parts thereof may be madewithout departing from the spirit of the invention.

We claim as our invention:

1. In a circuit interrupter, a U-shaped housing of onepiece moldedinsulated material, a pair of spaced terminal studs mounted on andextending into said U-shaped housing, stationary contact means mountedin said U-shaped housing on one of said studs, said stationary contactmeans comprising a plurality of pivoted main contact members, a pair ofmovable switch members pivotally mounted in said U-shaped housing on theother one of said studs, movable contact means carried by said pair ofmovable switch members cooperating with said stationary contact means,said movable contact means comprising a main movable contact --rigidlymounted between said switch members and-having portionsextending'laterally in opposite directions beyond said'switch membersengaging all of said stationary main contact members, a movable arcingcontact pivotally supported between'said movable switch memberscooperating with said stationary arcing contact, and an arc chute hingedon said stationary contact means adjacent said U-shaped housing andmovable to a position to provide access to said contact means.

2. A circuit interrupter comprising a U-shaped housing of one-piecemolded insulating material, a pair of spaced terminal studs mounted onand extending into said U-shapedinsulating housing, conducting membersrigidly secured to said terminal studs within said insulating housing,stationary contact means mounted on one of said conducting members, amovable switch member pivotally mounted in said U-shaped insulatinghousing on the other one of said conducting members, movable contactmeans carried by said movable switch member cooperating with saidstationary contact means, a projection on said one conducting member, anarc chute pivotally supported on said projection, and means on saidU-shaped insulating housing supporting said are chute in the normalpotition of said are chute to form continuous barriers between the polesof said interrupter, said stationary contact means and said movablecontact member being disposed entirely between said barriers.

3. Acircuit interrupter comprising a U-shaped housing of one-pice moldedinsulating material, a pair of spaced terminal studs mounted on andextending into said U-shaped housing, conducting members rigidly securedto said terminal studs within said 'U-shaped housing, stationary contactmeans mounted on one of said conducting -members, a movable switchmember pivotally mounted in said housing on the other one of saidconducting members, movable contact means carried by said movable switchmember cooperating with said stationary contact means, a hingeportion-on-said one conducting member, an arc chute pivotally supportedonsaid hinge portion and havingforward and reararcrunners therein, andinwardly extending shoulders on said U-shaped housing supporting saidare chute in the normal position of said are chute, and resilient meansconnected to said rear arc runner and biased against said projection toform an electrical connection between said rear arc runner ad said oneconducting member in all positions of said are chute.

4. A circuit interrupter comprising a U-shaped housing of one-piecemolded insulating material, spaced terminal studs mounted on andextending into said U-shaped housing, conducting blocks rigidly securedto said terminal studs, stationary cont-act means mounted within saidU-shaped housing on one of said conducting blocks, said stationarycontact means comprising a plurality of main contact fingers pivotallysupported on said one conductingblock and an arcing contact rigidlymounted on said one conducting block, movable contact means cooperatingwith said stationary contact means comprising a pair of spaced movableswitch arms pivotally supported within said U-shaped housing on theother end of said conducting blocks, operating means for said movableswitch arms, a single main moving contact member rigidly mounted betweensaid pair of movable switch arms and having contact portions extendinglaterally in opposite directions beyond the sides of said pair of switcharms engaging all of said plurality of main stationary contact fingers,a movable arcing contact having pivot means thereon, pivot notches inthe edges of said switch arms for receiving said pivot means topivotally support said movable arcing contact on said movable switcharms, means rigidly mounted on said main movable contac member engagingsaid pivot means and holding said arcing contact in said pivot notches,a bracket rigidly mounted on said main movable contact member, andspring means compressed between said bracket and said movable arcingcontact biasing said movable arcing contact in closing directionrelative to said movable switch arms.

5. A circuit interrupter comprising a U-shaped housing of one-piecemolded insulating material having a back portion and spaced integralside walls, spaced terminal studs mounted on said back portion andextending into said housing, conducting blocks rigidly mounted withinsaid U-shaped housing on said terminal studs Within said housing,stationary contact means mounted on one of said studs, movable contactmeans pivotally mounted within said U-shaped housing on the other ofsaid terminal studs cooperating with said stationary contacts, said sidewalls extending from said back portion farther than said movable contactmeans in the open position thereof, operating means for said movablecontact means, an outwardly extending projection intergral with said oneconducting block, an arc chute pivotally supported on said projection,and said U-shaped insulating housing having inwardly extending shoulderssupporting said are chute in its normal position.

6. A circuit interrupter comprising a channel-shaped housing ofone-piece molded insulating material, spaced terminal studs mounted onand extending into said housing, insulating bushings sourroundig saidterminal studs, said bushings having beveled surfaces thereon engagingbeveled surfaces on said housing to position and align said terminalstuds, stationary contact means mounted within said channel-shapedhousing on the inner end of one of said terminal studs, cooperatingmovable contact means pivotally mounted within said channel-shapedhousing on the other of said terminal studs, operating means for saidmovable contact means, a pivotally supported arc chute, the insulatingside walls of said are chute engaging the insulating side walls of saidchannelshaped housing to form continuous vertical barriers between thepoles of said interrupter, said vertical barriers extending outwardbeyond said movable contact means in the open position thereof.

7. A circuit interrupter comprising a channel-shaped member of one-piecemolded insulating material, spaced terminal studs mounted on andextending into said channel-shaped member, stationary contact meansmounted within said channel-shaped housing on the inner end of one ofsaid terminal studs, movable contact means pivotally mounted within saidchannel-shaped housing on the inner end of the other of said terminalstuds cooperating with said stationary contact means, operating meansfor said movable contact means, an arc chute pivotally supported on saidstationary contact means, the insulating side walls ofsaid arc chuteengaging .the insulating side wallsof said channel-shaped member to formcontinuous vertical barriers between the poles of said interrupterextending beyond said movable contact means in the open positionthereof, and the line of separation of said are chute and saidchannel-shaped member beingv below the top of said movable contactmeans.

8. A circuit interrupter comprising a channel-shaped housing of moldedinsulating material, spaced terminal studs mounted on and extending intosaid channel-shaped housing, insulating bushings surrounding saidterminal studs, said bushings having beveled surfaces thereon engagingbeveled surfaces on said channel-shaped housing to position saidterminal studs, resilient washers between the beveled suriace on saidhousing and the beveled surface on said bushing to compensate for anyirregularities on said surfaces, separable contact means mounted on theinner ends of said terminal studs within said insulating housing, and ahinged are chute having insulating side walls engaging the side walls ofsaid channel-shaped housing to form continuous barriers between thepoles of said interrupter extending beyond said contact means in theopen position thereof.

9. In a multi-pole circuit interrupter, a housing foreach pole unitcomprising a rear wall of insulating ma terial at the back of each poleunit and side walls of insulating material between the pole units, apair of spaced terminal studs of conducting material extending throughthe rear wall of insulating material for each pole, a bushing ofinsulating material surrounding said terminal studs at the back of therear wall of insulating material but not at the front thereof, a contacthinge member supported on one of said terminal studs of each pairsubstantially against the frontlof the rear wall of insulating material,a contact member supported on the other of said terminal studs of eachpair substantially against the front of the rear wall of insulatingmaterial, a switch arm hingedly supported adjacent one end on saidcontact hinge member on said one of the terminal studs, and a movablecontact adjacent the other end of the switch arm engageable with saidcontact member supported on the other of the terminal studs.

10. In a multi-pole circuit interrupter, a rear wall of insulatingmaterial at the back of each pole unit, side walls of insulatingmaterial between the pole units, a pair of spaced terminal studs ofconducting material extending through the rear wall of insulatingmaterial for each pole, a bushing of insulating material surroundingsaid terminal studs at the back of the rear wall of insulating materialbut not at the front thereof, a contact hinge member supported on one ofsaid terminal studs of each pair substantially against the front of therear wall of insulating material, a contact member supported on theother of said terminal studs of each pair substantially against thefront of the rear wall of insulating material, a switch arm hingedlysupported adjacent one end on said contact hinge member on said one ofthe terminal studs, a movable contact adjacent the other end of theswitch arm engageable with said contact member supported on the other ofthe terminal studs, an arc chute positioned over said switch arm withthe rear end wall of the arc chute approximately in line with theaforesaid rear wall of insulating material.

11. In a multi-pole circuit interrupter, a channelshaped member ofinsulating material for each pole, each of said channel-shaped membershaving a back wall and side walls between the pole units, a pair ofspaced terminal studs of conducting material extending through the rearwall of the channel-shaped member of insulating material for each pole,a bushing of insulating material surrounding said terminal studs at theback of the rear wall of said channel-shaped member but not of the frontthereof, a contact hinge member supported on one of said terminal studsof each pair substantially against the front of the rear wall of saidchannel-shaped member of insulating material, a contact member supportedon the other of said terminal studs of each pair substantially againstthe front of the rear wall of each of said channel-shaped members, aswitch arm hingedly supported adjacent one end on said contact hingemember on one of the terminal studs, and a movable contact adjacent theother end of the switch arm engageable with said contact membersupported on the other of said terminal studs.

12. In a multi-pole circuit interrupter, a channelshaped member ofinsulating material for each pole, each of said channel-shaped membershaving a back wall and side walls between the pole units, a pair ofspaced terminal studs of con-ducting material extending through the rearWall of the channel-shaped member of insulating material for each pole,a bushing of insulating material surrounding said terminal studs at theback of the rear wall of said channel-shaped members but not of thefront thereof, a contact hinge member supported on one of said terminalstuds of each pair substantially against the front of the rear wall ofsaid channel-shaped member of insulating material, a contact membersupported on the other of said terminal studs of each pair substantiallyagainst the front of the rear wall of each of said channel-shapedmembers, a switch arm hingedly supported adjacent one end on saidcontact hinge member on one of the terminal studs, a movable contactadjacent the other end of the switch arm engageable with said contactmember supported on the other of said terminal studs, and a hinged arcchute having the axis of the hinge approximately in the plane of therear wall of said channel-shaped member, the sides of said are chutemeeting the sides of said channel-shaped member.

13. In a multi-pole circuit interrupter, a channelshaped member ofmolded insulating material for each pole, each of said channel-shapedmembers having a rear wall and having side walls between the poles, apair of spaced terminal Studs of conducting material extending throughthe rear wall of each of said channel-shaped members, a bushing ofinsulating material surrounding said terminal studs at the back of therear wall of said channel-shaped members, the rear walls of saidchannelshaped members having integral portions of insulation surroundingand overlapping a portion of the insulating bushings surrounding saidterminal studs, stationary contact means on one of said terminal studsinside the back wall of said channel-shaped member, and cooperatingmovable contact means mounted on the other of said terminal studs insidesaid channel-shaped member.

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